Managing Predictive Maintenance

In many companies today, maintenance is not treated as a strategic business function. Over the last decade, however, it has been clearly shown that maintenance has tremendous impact on a company's profitability. In cases where maintenance doesn't seem to contribute to a company's profitability, it is usually due to the fact maintenance is never developed strategically.

By Terry Wireman, Senior Industry Analyst, Genesis Solutions, Ridgefield, CT October 10, 2003
Integrated approach to maintenance management
Preventive maintenance
Inventory and procurement
Work flows and controls
Technical and interpersonal training
Operational Involvement
Predictive Maintenance

In many companies today, maintenance is not treated as a strategic business function. Over the last decade, however, it has been clearly shown that maintenance has tremendous impact on a company’s profitability.

In cases where maintenance doesn’t seem to contribute to a company’s profitability, it is usually due to the fact maintenance is never developed strategically. The failure to integrate the components of a maintenance strategy also leads to excessive expenditures and a subsequent drain on profitability.

Integrated approach to maintenance management

Instead of the common fragmented approach to maintenance, an integrated approach is recommended.

A foundation must be in place to build the maintenance management process. The basics of preventive maintenance must be in place for any other part of the process to be successful. Once the PM foundation is in place, stores and procurement, workflow (including planning and scheduling, CMMS, and technical and interpersonal training provide the next level of strategic focus. The operations involvement, predictive, and reliability-centered maintenance (RCM) techniques build on this foundation. With sufficient data, the organization can focus on its asset strategy on total productive maintenance (TPM) and financial optimization. Once that level is achieved, all that is left is the continuous improvement loop of self-evaluation and benchmarking.

Each of these components is a building block for an integrated maintenance strategy (see illustration). While it is beyond the scope of this article to examine each of these components in depth, a brief overview to show the steps leading to a successful PdM program will be highlighted.

Preventive maintenance

The preventive maintenance program is the key to any successful maintenance strategy. The PM program reduces the amount of reactive maintenance to a level at which the other components of the maintenance strategy can be effective. However, most companies have problems keeping the PM program focused. In fact, surveys have shown that only 20% of companies in the United States feel their PM programs are effective.

This fact indicates that most companies need to focus on the basics of maintenance if they are to achieve any type of asset management process. Several studies have shown that up to 50% of all equipment failures in a plant are related to the neglect of PM basics, such as proper inspections, adjustments and torquing, and lubrication. Effective preventive maintenance activities would enable a company to achieve a ratio of 80% proactive maintenance to 20% (or less) reactive maintenance. Once the ratios are at least at this level, the other initiatives in the asset management process become more effective.

From the financial perspective, reactive maintenance typically costs 2 to 4 times what proactive maintenance costs, due to the inherent inefficiencies. Since the maintenance management strategies focus on ROI, it is critical to have a successful PM program as a foundation. Unless this foundation of effective PM is correctly developed, all subsequent activities will be suboptimized and incur unnecessary costs.

Predictive maintenance tools are designed to monitor the health of equipment, not to perform autopsies on failed equipment. From a PdM perspective, it is essential to have an effective PM program instituted, since a company would not want to invest in technology to correct a problem that is related to a neglect of basics.

Inventory and procurement

The inventory and procurement component must focus on providing the right parts at the right time for the asset repairs and maintenance. The goal is to have enough spare parts, without having too many spare parts.

An important function of the inventory and procurement component should be noted — having the right parts. Often, in an attempt to lower the inventory budget, the purchasing function will purchase all parts at low bid. This practice often leads to substandard parts being installed during routine maintenance replacements.

This situation has a dramatic impact on the predictive programs, since the substandard components will not perform as well as the original components, and premature failure will result. Many of the signs of premature failure will be detected by PdM techniques. However, with an excessive number of components to monitor, the predictive maintenance technicians will become over-taxed and many inspections delayed. These delays allow time for failures to occur. As a result, senior management will question the effectiveness of the PdM program, resulting in reduced funding and, ultimately, reducing the PdM effort to occasional checks of equipment in distress.

While it is not always necessary to purchase only OEM parts, purchasing equivalent-quality parts is essential.

Work flows and controls

This component of a maintenance management strategy involves documenting and tracking the maintenance work that is performed. This involves the use of a work order system to initiate, track, and record all maintenance and engineering activities, including predictive maintenance. The inclusion of the predictive activities is essential to track the amount of resources being expended while performing PdM activities. Unless this discipline is in place, data is lost, and true analysis can never be performed.

Unfortunately, many organizations record only a small part of their maintenance and engineering actions and virtually none of their PdM activities, so much data is lost. When it comes time to perform an analysis of the data, the analysis is incomplete and inaccurate. As a result, management doesn’t support the decisions made, and further degradation of their confidence in the maintenance department occurs.

Effective planning and scheduling are important to the predictive maintenance program for two reasons. The first is that maintenance technicians need to be scheduled for the PdM activities. The resource requirements for the PdM program need to be projected and tracked through the work order and planning and scheduling functions.

The second reason is that the PdM program will identify work activities that need to be performed on equipment so that an unplanned failure does not occur. Unless a disciplined approach is taken to planning and scheduling these activities, the work will not be performed in the timeframe necessary to prevent the projected failure. The repair will then be performed in a reactive mode, and the PdM effort will be viewed by senior executives as an unnecessary expense.


In most companies, there is sufficient work order data accumulated by the maintenance and engineering functions to require the computerization of the data flow. Computerized maintenance management system (CMMS) and enterprise asset management (EAM) software manages the functions discussed previously and provides information support for the maintenance management strategy.

From a Predictive Maintenance perspective, the CMMS/EAM system is usually interfaced to the predictive software system. There is usually an interface that allows triggers or alarms in the predictive software to generate work orders to make repairs that are identified by the PdM inspections. The work is tracked through the CMMS/EAM system allowing data to be posted in the equipment history, where analysis such as mean time to repair (MTTR), mean time between failure (MTBF) and total cost (expenses and savings) can be performed. A simplified flow diagram of this process is shown in the illustration.

Technical and interpersonal training

The technology in operations and maintenance requires that the organization has employees who have not only the technical skills required but also the interpersonal skills to work together.

Interpersonal skills development may include diversity training, team building training, and personal development training, such as coaching skills, time management skills, etc. This training is an enabler to allow the organization to begin to take more of a holistic view of itself, with everyone focusing on organizational improvement and not just departmental improvement. This training helps employees connect their job functions to the goals of the company.

Technical training ensures that the employees have the technical skills to contribute in the new roles and responsibilities they will assume. The first issue is the maintenance organization. It is imperative to evaluate the basic skills of the maintenance personnel, because studies have shown that over 50% of all equipment breakdowns occur due to the lack of the basics in maintenance. Once the basics are ensured, then the new, higher level skills required for advanced techniques (such as PdM) need to be defined and implemented.

With the maintenance organization’s skill level heightened, the focus is shifted to the operations department. It is also important to evaluate the operators’ skills in not only operating the equipment, but also in some of the maintenance basics that they can perform on their equipment. While this training is not as detailed as was given to the maintenance technicians, the concentration is still on ensuring that basics are performed correctly.

Operational Involvement

Operational Involvement requires the operations, production, and facilities departments to take ownership of their equipment to the extent that they are willing to support the maintenance and engineering department’s efforts. The aspects of involvement vary from company to company but typically include some of the following:

  • Inspecting equipment prior to start up

  • Making out work requests for maintenance

  • Recording breakdown or malfunction data for equipment

  • Performing some basic equipment service (e.g., lubrication)

  • Performing routine adjustments on equipment

  • Performing maintenance activities (supported by central maintenance).

    • The extent to which operations, production, and facilities are involved in maintenance activities may depend on the complexity of the equipment, the skills of the individuals, or even union agreements.

      An important point to understand is the goal of involving operations and facility personnel in maintenance-related activities is not to “downsize” the maintenance organization. The goal is to free up some of the maintenance and engineering resources to concentrate on more advanced maintenance management techniques such as predictive maintenance.

      Predictive Maintenance

      Once maintenance and engineering resources have been freed by the involvement of operations, resources should be refocused on the predictive technologies that apply to their equipment. In some cases, real-time monitoring of equipment conditions is part of the PdM program. For example, the devices monitoring the equipment may be connected to a building automation system, a distributed control system, or a PLC system and, all parameters monitored in a real-time environment.

      The focus for PdM is not to purchase all the technology available, but to investigate and purchase technology that solves or mitigates chronic equipment problems. The predictive inspections should be planned and scheduled utilizing the same techniques that are used to schedule the preventive tasks. As mentioned previously, all data should be recorded in or interfaced to the CMMS/EAM system.

      There are dozens of predictive maintenance technologies, and some have become virtually industry standards. Those “standard” technologies include vibration analysis, ultrasound, oil analysis, wear-particle analysis, and thermography.

      As has been shown, a predictive maintenance program is not a standalone strategy, but needs to be integrated into an overall asset management strategy. Companies need to realize that there are various components to an asset management strategy and that they need to be integrated to be effective.

      It is only through this understanding that maintenance management will eliminate waste and produce the maximum benefit to a company’s profitability.

      Author Information
      About the author…
      Terry Wireman has more than 20 yr of international experience as a consultative educator in industrial maintenance. He has authored numerous textbooks on maintenance practices and management and is a frequent presenter and trainer at major colleges and universities, technical societies, and conferences around the world. His latest book, Maintenance Management and Regulatory Compliance Strategies, is available from Industrial Press, Inc., 200 Madison Ave., New York, NY 10016; 212-889-6330;
      Headquartered in Ridgefield, CT, GenesisSolutions offers consulting services in asset management and MRO optimization, enterprise asset management (EAM) technology and engineering services. Visit